Preparation of Ethanol from Sucrose

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Experiment #1 Preparation of Ethanol from Sucrose

Based on R. Weglein & C.L> Yau, CHEM 203 Experiments in Organic Chemistry II Laboratory, 5th Edition, 2006, p29-32.

Statement of Purpose: An aqueous solution of ethanol is prepared by the fermentation of sucrose. The percent alcohol is the resulting solution and the percent conversions of the sucrose are to be determined.

Introduction: Sucrose is a molecule containing glucose and fructose.

http://faculty.tcc.fl.edu/scma/phelpsj/experiments/ethanol.pdf

Balanced Equation:
yeast
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C12H22O11(s) + H2O 4C2H5OH(l) + 4CO2

Table of Reagents and Expected Products:

Reagent| MW| # of moles| Volume and Mass| Properties|
SucroseC12H22O4| 342.2965 g/mol| 0.0500 mol| 10.75 mL17.134 g| d= 1.59 g/mL| WaterH2O| 18.015 g/mol| 5.55 mol| 100 g100 mL| d= 1 g/mL| EthanolC2H5OH| 146.07 g/mol| 0.2000 mol| 11.68 mL9.214 g| d= 0.789 g/ml| Carbon DioxideCO2| 44.01 g/mol| 0.2000 mol| 8.802 g4452 mL| d= 0.0020g/mL| Reference 1: http://wolframalpha.com accessed 12 June 12

Calculations:

Volume of sucrose = 17.1 g / 1.59 g/mL = 10.75 mL
Mass of water = 100 mL (1 g/mL) = 100 g
Moles of water = 100 g / 18.015 g/mol = 5.55 mol

1 mol sucrose=4 mol ethanol1 mol sucrose=4 mol carbon dioxide ¼=0.0500mol/x1/4=0.0500mol/0.2 mol
x=0.2 mol ethanol

Experimental Procedure:
The procedure followed is given in Weglein and Yau, CHEM 203 Experiments in Organic Chemistry II Laboratory Manual; 5th Edition, Academx: Baltimore, MD, 2007, p29-32.

Results and Discussion:

mL Collected| Temp °C|
0| 22.2|
5| 92.7|
10| 94.9|
15| 96.5|
20| 97.7|
25| 98.5|

N20D=1.3569
% ethanol=34.8% from graph
Vethanol=25.05mL(0.348) = 8.717 mL ethanol
MassEtOH= 8.717mL(0.785g/mL)=6.843g
% conversion=(6.843g/9.214)100=74.27%

The graph depicted in Weglein and Yau shows that from the Refractive Index taken (1.3569) 34.8% ethanol was produced from sucrose. From...
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